Charles E. Benham — Liquid Inclusions in Glass. 133 



usual process of firing in the brick kiln. To avoid any risk of a violent 

 explosion the tube used was only about 3 inches long and ^ in. 

 outside bore. This was nearly filled with water and hermetically 

 sealed in a gas flame at each end. The tube was embedded in the 

 middle of the soft brick so as to ensure a complete sealing in of the 

 liquid contents. The brick, duly marked for identification, was 

 placed amongst the others in the kiln and exposed to the usual 

 period of firing. The idea was to ensure that the glass when molten 

 should come into contact with water vapour above the critical 

 temperature, and that in this way inclusions should be formed in 

 the substance of the glass. 



Fig. 2. — Liquid inclusions in resin which had been immersed in boiling water 

 containing suspended gamboge particles. Some of the spherules show 

 a central air bubble, while others are completely filled with the liquid. 



The experiment was successful, the glass showing microscopic 

 inclusions, with a bubble of vapour comparable with those found 

 in quartz, affording a possible clue to the formation of inclusions in 

 that mineral. 



As will be seen from the drawing (Fig. 3), the glass inclusions were 

 spherical in form. The sketch was made with camera lucida attach- 

 ment. There were also a good many impurities imprisoned showing 

 as specks and smudgy masses which are not rendered in the drawing 

 as having no special bearing on the experiment, but the fibrous 

 state of much of the glass has been diagrammatically reproduced. 

 This fibrous condition is due to the fact that the heat was 



